Chevron Corporation announced that the Pacific Santa Ana, a deepwater drillship built to Chevron's specifications, has arrived in the Gulf of Mexico to work for Chevron under a five-year contract with a subsidiary of Pacific Drilling S.A. (NYSE: PACD). Pacific Santa Ana is the first drillship designed with the capacity to perform dual gradient drilling (DGD).

"Pacific Santa Ana will enable us to demonstrate dual gradient drilling, which has the potential to change the way deepwater wells are drilled," said George Kirkland, vice chairman, Chevron Corporation. "This new process builds on our record of technology leadership in deepwater."

"The addition of Pacific Santa Ana as Chevron's fifth drillship in the deepwater Gulf of Mexico demonstrates our long-term commitment to developing America's energy resources," said Gary Luquette, president of Chevron North America Exploration and Production Company. "We are bullish on the Gulf, where robust energy exploration and development is vital to our nation's economy and energy security."

Unlike conventional deepwater drilling, which uses a single drilling fluid weight in the borehole, dual gradient drilling employs two weights of drilling fluid – one above the seabed, another below. This allows drillers to more closely match the pressures presented by nature and effectively eliminates water depth as a consideration in well design. DGD also allows drillers to more quickly detect and appropriately react to downhole pressure changes, which can enhance the safety and efficiency of deepwater drilling operations.

Pacific Santa Ana is equipped with a DGD riser, a mud lift pump handling system, six mud pumps – three for drilling fluid and three for seawater – extensive fluid management system enhancements and more than 72,000 feet of DGD-related cables. After additional equipment is installed and tested, Pacific Santa Ana will be used for exploratory and development drilling in the deepwater Gulf of Mexico.